fix: properly precompute the WebSocket frames

The named import is not supported in some cases:

> node_modules/socket.io-adapter/dist/index.js:170
>            packetOpts.wsPreEncodedFrame = ws_1.WebSocket.Sender.frame(data, {
>                                                          ^
>
> TypeError: Cannot read properties of undefined (reading 'Sender')
>     at RedisAdapter._encode (/.../node_modules/socket.io-adapter/dist/index.js:170:59)
>     at RedisAdapter.broadcast (/.../node_modules/socket.io-adapter/dist/index.js:117:37)

Related: socketio/socket.io-redis-adapter#478

lib/index.ts

@@ -1,6 +1,8 @@
 import { EventEmitter } from "events";
 import { yeast } from "./contrib/yeast";
-import { WebSocket } from "ws";
+import WebSocket = require("ws");
+
+const canPreComputeFrame = typeof WebSocket?.Sender?.frame === "function";
 
 /**
  * A public ID, sent by the server at the beginning of the Socket.IO session and which can be used for private messaging
@@ -231,7 +233,11 @@ export class Adapter extends EventEmitter {
   private _encode(packet: unknown, packetOpts: Record<string, unknown>) {
     const encodedPackets = this.encoder.encode(packet);
 
-    if (encodedPackets.length === 1 && typeof encodedPackets[0] === "string") {
+    if (
+      canPreComputeFrame &&
+      encodedPackets.length === 1 &&
+      typeof encodedPackets[0] === "string"
+    ) {
       // "4" being the "message" packet type in the Engine.IO protocol
       const data = Buffer.from("4" + encodedPackets[0]);
       // see https://github.com/websockets/ws/issues/617#issuecomment-283002469